1. Field of the Invention
This invention relates to a liquid atomizing device and more particularly, to a device for atomizing liquid fuel in a gas turbine. It is a rotary device which atomizes liquid centrifugally.
2. Description of the Prior Art
The prior art of which the inventor is aware as being relevant to this invention includes a rotary liquid atomizing device having a disc secured to a rotary shaft for rotation therewith, and a stationary nozzle which emits the liquid to be atomized. The liquid emitted from the nozzle strikes against the disc and by virtue of the centrifugal force created by the rotation of the disc, the liquid is scattered in atomized form as it leaves the disc. Centrifugal atomization, however, requires to a certain extent adherence of liquid to the surface of the rotating disc. If the speed of rotation of the disc in the device under discussion is higher than a certain level, the liquid emitted from the nozzle is splashed by the disc without properly adhering thereto, so that little or no atomization can be accomplished. It is found that effective atomization can be obtained only when the speed of rotation of the disc is not greater than 10 meters per second, and that if it is in excess of 20 meters per second, no atomization is possible.
Another device known in the art comprises a rotary hollow cylinder having an open end through which the liquid to be atomized is injected into the cylinder. The cylindrical wall of the cylinder is provided therethrough with a plurality of outlet holes through which, as the cylinder rotates, the liquid introduced into the cylinder is centrifugally emitted to form a spray of atomized liquid. This device is, however, notorious for its inability to produce a satisfactorily fine spray of atomized liquid, however small the outlet holes may be made in diameter. This is experimentally demonstrated as the results will hereinafter be discussed with reference to FIG. 5 of the accompanying drawings.
There is also known a liquid atomizing device having a similar hollow rotary shaft provided with a swirl nozzle through which the liquid introduced into the hollow interior of the shaft is centrifugally emitted in atomized form during the rotation of the shaft. The wall of the hollow shaft is pierced with a hole which is perpendicular to the axial bore of the shaft, and in which the swirl nozzle is mounted. This device permits atomization of liquid to finer particles than those obtained by the device described in the immediately preceding paragraph, but nevertheless, fails to produce a satisfactorily fine spray of atomized liquid. As the swirl nozzle is subjected to a large centrifugal force during the rotation of the shaft, it can unintentionally be disengaged from the shaft unless it is very firmly secured to the shaft.